Estimation of Lightning-Generated NO_(x) in the Mainland of China Based on Cloud-to-Ground Lightning Location Data

Lightning-generated nitrogen oxides(LNO_(x))have a major influence on the atmosphere and global climate change.Therefore,it is of great importance to obtain a more accurate estimation of LNO_(x).The aim of this study is to provide a reference for the accurate estimation of the total LNO_(x) in the mainland of China based on cloud-to-ground lightning(CG)location data from 2014 to 2018.The energy of each CG flash was based on the number of return strokes per CG flash,the peak current of each return stroke,and the assumed CG breakdown voltage.The energy of intracloud lightning(IC)was based on the estimated frequencies of IC and the assumed energy of each IC flash.Combining the energy of lightning and the number of nitric oxide(NO)molecules produced by unit energy(ρno),the total LNO_(x) production in the mainland of China was determined.The LNO_(x) in the mainland of China estimated in this study is in the range(0.157-0.321)×10^(9) kg per year[Tg(N)yr-1],which is on the high end of other scholars’works.Negative cloud-to-ground lightning(NCG)flashes produce the most moles of NO_(x),while positive cloud-to-ground lightning(PCG)flashes produce the least total moles of NO_(x).The breakdown voltage of PCG is greater than that of IC or NCG,while the latter has a greater output of LNO_(x).

LLSDA: Design and Implementation of Lightning Location Data Analysis and Visualization

Visualizing lightning location data is necessary in analyzing and researching lightning activity patterns.This article uses C#and the cross-platform.NET framework to develop a lightning location data analysis class library and the data-driven client to help lightning researchers improve work efficiency by avoiding repeated wheel invention.Lightning Location System Data Analyzer(LLSDA)is a suite of software tools that includes a.NET class library for software developers and a desktop application for end users.It supports a wide range of lightning location data formats,such as the University of Washington Global Lightning Location System(WWLLN)and Beijing Huayun Dongfang ADTD Lightning Location System data format,and maintains scalability.The class library can easily read,parse,and analyze lightning location data,and combined with third-party frameworks can realize grid analysis.The desktop application can be combined with MeteoInfo(a GIS open-source project)for secondary development.

Power Network Lightning Accident Quick Inquiry with the Lightning Location System

At present, lightning is one of the 10 natural disasters, and it is also the top environmental factor of power interruption. It often causes huge losses to the electric system. The Wuhan High Voltage Institute of the State Grid Corporation of China and Huazhong University of Science and Technology have been researching and developing lightning location systems （LLSs） since the late 1980s. In the mid-1990s, a lightning detection network was created in 29 provinces and cities in China. It is primarily applied to rapidly find lightning accidents, which greatly reduces power interruption. Also, it ensures high efficiency and safe operation of the electricity system. Remarkable benefit is achieved. China＇s LLS went through an ＂orientation positioning - time difference positioning - integrated positioning＂ development process. The positioning precision, detection efficiency, degree of automation, practicability and applied range are improved. Also, a lightning information system plan of the national network has been implemented, which services the whole society.

Lightning Nowcasting with an Algorithm of Thunderstorm Tracking Based on Lightning Location Data over the Beijing Area

A thunderstorm tracking algorithm is proposed to nowcast the possibility of lightning activity over an area of concern by using the total lightning data and neighborhood technique.The lightning radiation sources observed from the Beijing Lightning Network(BLNET)were used to obtain information about the thunderstorm cells,which are significantly valuable in real-time.The boundaries of thunderstorm cells were obtained through the neighborhood technique.After smoothing,these boundaries were used to track the movement of thunderstorms and then extrapolated to nowcast the lightning approaching in an area of concern.The algorithm can deliver creditable results prior to a thunderstorm arriving at the area of concern,with accuracies of 63%,80%,and 91%for lead times of 30,15,and 5 minutes,respectively.The real-time observations of total lightning appear to be significant for thunderstorm tracking and lightning nowcasting,as total lightning tracking could help to fill the observational gaps in radar reflectivity due to the attenuation by hills or other obstacles.The lightning data used in the algorithm performs well in tracking the active thunderstorm cells associated with lightning activities.

Application of Data from a Lightning Location System in Huai'an Region

Based on data of cloud-to-ground lightning detected by a lightning location system in Jiangsu Province from 2007 to 2012and data of thunderstorm days from seven meteorological observation stations in Huai'an during 1961-2012,the spatial and temporal distribution characteristics of cloud-to-ground lightning in Huai'an were analyzed.The results show that the total frequency of cloud-to-ground lightning in one day was closely related to the intensity and frequency of thunder and lightning.The seasonal variations in the total frequency of cloud-to-ground lightning in Huai'an.The total frequency was shown in unimodal distribution,and the extreme values always appeared in July or August.Most cloud-to-ground lightning was negative,and its frequency accounted for about95.3% of the total frequency.Cloud-to-ground lightning density was high in the south of Huai'an and low in the north,and the serious and very serious ground flash zones concentrated in the south of Hongze County,and most parts of Xuyi and Jinhu County,so lightning protection should be an important task particularly in these regions.

Revision of CG Flash Density Based on Lightning Location Data

Using the data of the Lightning Location System( LLS) over Hubei Province,through the analysis of the distribution characteristics of CG( Cloud-to-Ground) flash density in 2015,it was found that the layout of the detection station had influence on the spatial distribution of lightning.Grid CG flash density data were used to characterize the spatial distribution of the CG flash,and station distance factor was used to characterize the detection station layout. The result showed that there existed negative correlation between density and factor,significant correlation between the density component and the factor for the lightning current amplitude of 5 to 30 kA,and insignificant correlation between >30 kA of density component and factor. So it is necessary to revise the density to eliminate the influence of the station layout. On the basis of the linear regression method and its residual theory,the revision model of the grid CG flash density and the statistical model of relative detection efficiency were established. The result consistency of segment and non-segmented revision of the density was verified. Through the contrastive analysis of theoretical detection efficiency and relative detection efficiency,the feasibility for revision method of CG flash density and the statistical method of relative detection efficiency was also verified.

Error Correction of Lightning Location Data

[ Objective] The study aimed to correct error of lightning location data with small amplitude. [ Method] Using the curve fitting toolbox of matlab mathematical software, the distribution of lightning location data in Chongqing during 1999 -2008 was fitted based on logarithmic normal distribution function, and the specific characters of lightning data with current amplitude from -10 to 10 kA were analyzed. [ Result] During 1999 - 2008, the frequency of lightning with current amplitude from -10 to 10 kA in Chongqing City accounted for 4.93% of total frequency, while the fre- quency of lightning with current amplitude from -5 to 5 kA accounted for only 1.27%, lower than 2%, according with the conventional deletion proportion in China. Lightning data with current amplitude from -5 to 5 kA caused a great disturbance to the fitting effect, so the fitting effect was the best after these lightning data was deleted. After the lightning location system of Chongqing City was upgraded in 2005, the frequency of lightning with current amplitude from -10 to 10 kA decreased, and there were obvious changes in the frequency of lightning with current amplitude from -10 to -5 kA and from 5 to 10 kA, while the frequency of lightning with current amplitude from -5 to 5 kA was small and stable, so these data could be deleted. [Conclusion] The research could provide theoretical references for error correction of lightning location data with small amplitude in Chongqing City.

Design and Implementation of Lightning Analysis Software Based on Lightning Location System Data

This paper discusses the steps about how to design and implement software based on lightning location system data and its localization map.The system contains four major modules such as real-time lightning monitoring,historical query,lightning intensity zoning,lightning disaster statistics,etc.The system is able to automatically generate real-time lightning monitoring image,lightning animation,and lightning intensity zoning image,which contributes to the high accuracy of the calculation results and the efficiency of data analysis.The paper also points out the deficiencies of software life cycle management and proposes actionable solutions.

Development of a low-frequency magnetic lightning mapping system(LFM-LMS)in North China:validation and preliminary results

A low-frequency magnetic lightning mapping system(LFM-LMS)was built during the SHAndong Triggered Lightning Experiment(SHATLE),based on continuous measurements of magnetic field radiation from lightning.The hardware and source-mapping techniques used by the LFM-LMS were introduced;both Monte Carlo simulations and the observation of rocket-triggered lightning examples were employed to examine the location accuracy and detection effectiveness of the LFM-LMS.We estimated that the system’s location accuracy about 100−200 m horizontally and~200 m vertically.A natural intra-cloud lightning flash and a rocket-triggered lightning flash,both with intricate structures and discharging processes,were examined using the three-dimensional mapping results.The progressing path of negative lightning leaders is usually well-defined,and its propagation speed is estimated to be(0.5−1.4)×10^(6)m/s.In summary,the LFM-LMS can reconstruct the three-dimensional morphology of lightning flashes;this technology provides a efficient method for investigating the characteristics of lightning development,as well as the overall electrical strucuture of thunderstorms.

Temporal and Spatial Distribution of Lightning Activity in Ulanqab City

From January 2020 to December 2021,Ulanqab Meteorological Bureau of Inner Mongolia used VLF/LF lightning locator to carry out three-dimensional lightning monitoring in Ulanqab City,and compared with ADTD lightning location data in the same period.The results show that both VLF/LF lightning locator and ADTD lightning locator had excellent monitoring ability for lightning during flood season in Ulanqab.VLF/LF lightning locator was slightly superior to ADTD lightning locator in observation accuracy,the observation ability of low-current cloud-to-ground lightning,intracloud lightning observation and so on.There were obvious temporal and spatial characteristics of cloud-to-ground lightning during flood season in Ulanqab,and there was a certain correlation between the areas where lightning appeared frequently and surface water.Intracloud lightning was mainly concentrated at a height of 1-7 km.Negative cloud-to-ground lightning accounted for about 75%of total cloud-to-ground lightning,and negative intracloud lightning accounted for 39%of total intracloud lightning.

Characteristics of Cloud-to-ground Lightning during a Squall Line Process outside of the Subtropical High

Based on the monitoring data of cloud-to-ground( CG) lightning positioning network and Doppler weather radar as well as MICAPS1°× 1° objective analysis field,a squall line process outside of the subtropical high in low-latitude plateau on May 7,2010 was analyzed. The results showed that wind direction shear between low and high levels and low-level convergence zones provided favorable circulation background for the strong thunderstorm process,while high energy and high humidity,strong thermal instability and ascending motion at low and middle levels offered beneficial environmental conditions for the formation of the thunderstorm. 9 620 return strokes of cloud-to-ground lightning were monitored by the lightning positioning network,and cloud-to-ground lightning was distributed like bands between 584 and 586 hP a. The occurrence of cloud-to-ground lightning was mainly related to echo top and echo intensity at-10 ℃ stratification height,and it mainly appeared in zones where echo top height was larger than 13 km and echo intensity at-10 ℃ stratification height was 35-40 dB Z. Wind convergence and maintaining of high radial velocity were favorable for the development of convective echoes and occurrence of cloud-to-ground lightning.

Study on the Scope of Small Amplitude of Cloud-to-ground Lightning in Lightning Weather Monitoring

Based on lightning location data in Chongqing region during 1999-2008,the frequency of lightning in various amplitude ranges and its annual variations were analyzed firstly.Afterwards,with the aid of matlab mathematical software,the distribution of the lightning location data was fitted using logarithmic normal distribution function.The results showed that after data of cloud-to-ground lightning with current amplitude from-5 to5 kA were deleted from lightning location data,the statistical characteristics of cloud-to-ground lightning could be reflected well.Meanwhile,lightning with current amplitude from-5 to 5 kA accounted for 1.05%（less than 2%）,which accorded with the detection principle of lightning position indicator（there existed error detection）.Therefore,cloud-to-ground lightning with current amplitude of-5-5 kA in lightning location data of Chongqing region was defined as small amplitude of cloud-to-ground lightning,which could provide scientific references for the processing of lightning location data in Chongqing region as well as analysis and quality control of lightning location data in other regions.

应用脉冲回波的避雷线断线检测系统研究

为高效率、低成本地检测风力发电机组桨叶避雷线断线位置,设计基于脉冲回波的避雷线断线检测系统。该系统以单端行波法为原理,由信号发生模块,传感器模块,信号采集模块、控制器模块四部分构成。信号发生模块负责产生行波脉冲信号,传感器模块负责采集回波信号,信号采集模块负责将采集到的回波信号处理转化送给控制模块,控制模块负责分析回波信号,判断故障类型和故障点位置。该文对各个模块的电路和性能参数进行设计,搭建整体的检测系统。经实验验证,该系统可以精准的实现断线判断,并获得断线位置,测量误差精确到0.5 m以内。

基于归闪的湖北省两套闪电定位系统对比分析

为研究湖北省两套闪电定位系统,在归闪的基础上研究分析了2015—2020年湖北地区地闪数据,对闪电频次、时空分布、电流强度月分布、雷电流幅值累积概率等主要参数进行了比对分析,研究结果表明:ADTD-2系统在定位正地闪强度存在局部异常值外,比ADTD-1系统具有更高的探测效率,其中正地闪的探测效率比负地闪提升幅度更高,探测负地闪回击的时间分辨率也比ADTD-1系统高,ADTD-2闪电数据整体优于ADTD-1数据。

雷击故障下的分布式故障监测装置定位精度测试方法

分布式故障监测装置广泛应用于输电线路的故障定位领域,而产品质量参差不齐,部分厂家仅通过行波电流或者工频电流的变化进行故障定位,定位精度存在较大问题。为此,该文提出了一种兼顾行波电流和工频电流模态变化的测试方法。首先,开展了行波电流和工频电流波形的时序逻辑设计,并提出了精度测试的方法。然后,基于仿真和试验方法,对电流探头进行了选型设计。最后,研制了分布式故障监测装置测试系统,并完成了测试精度的影响因素研究。研究结果表明:测试过程中,雷击故障过渡时长小于1个周波,基本实现雷击故障波形时序的复现;电流探头A621和TRCP3000可配合进行测试,基本满足10~1000A行波电流测量的要求;两路雷电流波前时间差范围为1~100μs,实现了故障点位置的随机设定;db1测试精度优于db4,db4小波系数的鲁棒性优于db1,当信噪比大于20dB时,即可满足测试标准的要求。该研究结果可为分布式故障监测装置雷击故障下的定位精度改善提供技术支撑。

全并联AT牵引供电系统雷击故障测距多路径行波算法研究

针对AT变压器和并联结构导致行波传播路径复杂,行波波头性质难以有效识别和行波色散现象,线路频变参数特性导致波速不稳定的问题,提出一种基于多路径行波测距方法。基于上下行电流行波传播的差异性,利用电流相似度识别故障区段。探讨全并联AT牵引网结构对行波传播特性的影响,并对电流、电压行波传播路径进行标定。基于多路径电流、电压行波极性分析,筛选出用于故障测距的多路径行波,以推导出消去波速的测距方程。仿真表明:所提测距方法可以有效识别波头性质,且计算故障距离基本与波速无关,不受牵引网区段长度、结构影响。

基于山区大气电场演变特征与雷电定位数据的雷电临近预警方法

由于高原山区雷暴活动具有尺度小、离散性强的特点,实现山区重点资源区域的雷电灾害准确预警存在较大困难。考虑到雷暴时空演变与地面大气电场特征的关联关系,提出了一种基于大气电场监测数据与实时雷电定位信息的山区雷电临近预警方法。通过分析典型高原山区不同雷暴发展情况下的大气电场演化特性,发现山区大气电场可作为雷电定位数据的补充源,充分表征雷云剧烈放电和雷暴临近发展的特征信息。在预警过程中,首先将大气电场形态学梯度提取的快速抖动、暂态突变特征与时空匹配的地闪活动特征输入堆叠稀疏自编码器网络模型,判断监测区域附近是否出现雷云放电迹象,再利用雷暴距离变化或者电场波形变化判断雷电活动的临近趋势,最后综合两者的结果完成半径15km监测区域的雷电活动短时预警。在2023年云南山区雷雨季节的雷暴算例分析中,通过双源数据共同提取的山区雷暴活动预警特征的有效识别,可以实现预警准确率为90%,约44%的警报提前时间不小于30 min。

云南省两套闪电定位系统地闪回击参数对比及探测性能分析

根据2017—2020年云南省ADTD二维和VLF/LF三维闪电定位系统观测资料,对比两套系统地闪回击参数分布差异。在实际回击位置和雷电流强度信息难以获得的情况下,研究利用两套系统反演资料对相同回击事件的识别匹配和时空阈值选取方法,分析相对定位偏差。结果表明:两套系统的回击密度、雷电流幅值在滇东、滇西南和滇西北等地的空间分布差异明显,由三维系统得到的回击密度较大,但二维系统雷电流幅值均值更高。两套系统均以单回击地闪占比更高,正地闪中的单回击地闪比重较负地闪更大,三维系统对于0~5 kA负回击小幅值电流的探测效率有所提高。通过采用10km、1 ms的时空阈值匹配窗口,得到两套系统对于同一次回击的相对定位时间差主要集中在0.05 ms内,距离偏差集中在1 km内。系统匹配回击在滇中、滇西南的时空偏差较小,滇西北的偏差较大。从回击极性、相关系数、相对误差、幅值比及幅值累积概率等方面,分析得到两套系统对于相同回击事件的电流强度反演结果一致性较好,验证了应用系统反演资料对于同一回击事件的识别匹配方法是客观可靠的。

热带地区雹暴的闪电活动-动力-微物理特征研究

基于低频电场变化探测阵列三维闪电定位系统和S波段双偏振天气雷达数据, 对海南岛2021年6月24日一次雹暴过程的闪电活动和云内动力与微物理特征进行了详细的分析.结果显示: 该雹暴闪电活动以云闪为主, 占总闪的85.38%.降雹前发生的地闪以正地闪为主, 在降雹前25 min内, 正地闪频数占总地闪频数的60%, 高于一般雷暴正地闪活动比例.在雹暴成熟阶段, 上升气流出现两次增强, 而闪电频数的增加均滞后于上升气流增强的时段, 同时, 闪电频数的增加也可能与对流单体的合并有关.结合模糊逻辑判断法对云内降水粒子的识别, 计算了总闪与冰相粒子的相关系数, 其中霰和冰晶粒子与总闪相关性较高, 相关系数分别为0.76和0.83.根据闪电辐射源的空间分布特征, 推测该雹暴降雹前为反三极性电荷结构, 正电荷区位于约7~9.5 km(~-10 ℃至-25 ℃).